植物生态学报 ›› 2014, Vol. 38 ›› Issue (10): 1124-1134.doi: 10.3724/SP.J.1258.2014.00107

• 研究论文 • 上一篇    下一篇

棉花幼苗叶片光合特性对低温胁迫及恢复处理的响应

武辉, 戴海芳, 张巨松*, 焦晓玲, 刘翠, 石俊毅, 范志超, 阿丽艳·肉孜   

  1. 新疆农业大学农学院; 教育部棉花工程研究中心, 乌鲁木齐 830052
  • 收稿日期:2014-05-19 修回日期:2014-07-15 出版日期:2014-10-01 发布日期:2014-10-22
  • 通讯作者: 张巨松 E-mail:xjndzjs@163.com
  • 基金资助:

    国家“十二五”科技支撑计划项目;新疆维吾尔自治区“十二五”科技支撑课题

Responses of photosynthetic characteristics to low temperature stress and recovery treatment in cotton seedling leaves

WU Hui, DAI Hai-Fang, ZHANG Ju-Song*, JIAO Xiao-Ling, LIU Cui, SHI Jun-Yi, FAN Zhi-Chao, and ALIYAN·Rouzi   

  1. College of Agronomy, Xinjiang Agricultural University; Research Center of Cotton Engineering, Ministry of Education, Ürümqi 830052, China
  • Received:2014-05-19 Revised:2014-07-15 Online:2014-10-01 Published:2014-10-22
  • Contact: ZHANG Ju-Song E-mail:xjndzjs@163.com

摘要:

为研究低温逆境及恢复处理下棉花幼苗光合特性响应机制, 丰富棉花苗期在不同胁迫水平下的抗寒机制及为应对自然条件下突发的低温冷害提供理论依据, 以‘新陆早33号’ (冷敏感)及‘中棉所50号’ (高耐寒)两个品种为试材, 采用人工模拟低温方法, 研究不同温度和处理时间下棉花幼苗光合气体交换参数、光能转化及传递的表现和恢复能力, 并通过测定胁迫解除后叶片的光合光响应曲线来分析叶片对光环境的适应能力。结果表明, 在较低强度低温逆境(15 ℃或24 h胁迫)中, 叶片净光合速率(Pn)、气孔导度(Gs)、气孔限制值、胞间CO2浓度、最大光化学效率、光适应下最大光化学效率、实际光化学效率、相对电子传递速率变化幅度较小, 且胁迫解除后可恢复正常, 此时叶片光系统II (PSII)光反应中心受损可逆, Pn下降主要因气孔闭合引起。随着胁迫强度增加, 各测试指标变化显著, 且恢复表现较差, 此时叶片PSII光反应中心光能吸收、转化和电子传递受到严重阻碍, Pn下降原因由气孔限制因素转变为非气孔限制因素。低温胁迫导致叶片对光辐射的利用能力下降, 随着胁迫温度降低, 叶片最大净光合速率、表观量子效率及光饱和点快速下降, 光补偿点及暗呼吸速率则呈上升趋势。低温胁迫可导致棉花幼苗叶片对光环境适应能力降低, PSII反应中心对激发能捕获、活跃化学能转化及光合电子传递速率快速下降, CO2固定能力降低, 最终导致光合能力下降。强耐寒品种则能在低温逆境中保持较高的光能转化、电子传递和弱光利用效率, 亦可通过减少暗呼吸消耗和调整Gs降低幅度和速度来保持较高的光合速率, 提高恢复能力, 增强植株抗逆性。

Abstract:
Aims The objective of this study was to investigate the responses of photosynthetic traits to varying degrees of low temperature stress and recovery treatment, in order to provide a theoretical basis for enhancing the cold tolerance of cotton seedlings and avoiding chilling damage under natural conditions.
Methods The cotton cultivars ‘Xinluzao 33’ (cold sensitive) and ‘Zhongmiansuo 50’ (cold tolerant) were used in this study. Gas exchange parameters, energy conversion and electron transmission of seedling leaves were determined under different levels and durations of low temperature stresses and subsequent recovery treatment. The adaptive capacity to light was also analyzed by developing photosynthetic light response curves of leaves under recovery treatment after 48 h of low temperature stresses.
Important findings The results showed that the values of net photosynthesis (Pn), stomatal conductance (Gs), stomatal limitation (Ls), intercellular CO2 concentration (Ci), maximum photochemical efficiency (Fv/Fm), maximal photochemical efficiency in light adaptation (Fv′/Fm′), actual quantum yield (ΦPSII) and relative electron transport rate (rETR) varied very little such that they reached the normal levels after being released from less-intense chilling stresses (15 °C or 24 h). In this situation, the damage of photosystem II (PSII) reaction center was reversible and the Pn was subjected to stomatal limitation. With decreasing temperature and treatment time, the parameters changed significantly and performed less well under recovery treatment in the two cotton cultivars. The limiting factor for Pn had changed from stomatal to non-stomatal, and the absorption, conversion of light energy, and electron transmission were severely inhibited. In addition, with a decrease in temperature, the maximum photosynthetic rate (Pnmax), the initial slope of photosynthetic light response curve (AQY) and the light saturation point (LSP) of cotton seedlings declined rapidly, and the light compensation point (LCP) and dark respiration (i.e. mitochondrial respiration; Rd), displayed an upward trend, indicating that the ability of radiation utilization decreased. Those results indicated that, low temperature stress decreased the adaptability to light environment, the activity of PSII reaction centers and photochemical electron transfer rate, inhibited pathways of photosynthetic electron transport, and reduced the CO2 fixation capacity, which led to the structural damage of photosynthetic apparatus and functional reduction in photosynthetic capacity. The cold tolerant cultivar could maintain higher photosynthetic rate by keeping higher photochemical electrontransfer, transport, and low-light utilization ability, and lower respiration, and by adjusting the reduction of Gs to be more rapid and sensitive, which could enhance the recovery capability and chilling adaptability.